Abstract: Disclosed herein is a base station that extracts a ranging channel signal from a received signal partially correlates each of a plurality of ranging channel signals and each of ranging codes according to ranging modes, and selects a ranging channel signal greater than a first threshold value, the plurality of ranging channel signals being signals according to plurality of time delays of a ranging channel signal. In addition, the base station correlates each of the selected ranging channel signal and each of corresponding ranging code, selects a ranging channel signal having the maximum correlation value, and estimates receiving power by using a time delay corresponding to the selected ranging channel signal.

Abstract: A downlink beamforming apparatus and a transmission apparatus including the same includes a subcarrier based user identifier for dividing subcarriers according to users, a beamforming weight buffer for storing first beamforming weights for the subcarriers by each of transmitting antennas, an interpolator for outputting second beamforming weights for each transmitting antenna by interpolating the first beamforming weights, and a signal reproducer for reproducing the signal for each transmitting antenna. Subcarriers are allocated to the signal by each user; and a complex multiplier multiplies the signal for each transmitting antenna by the second beamforming weights.

Abstract: A system in an asynchronous mobile communications system and located in a mobile station for determining use of space-time block-coding-based transmit diversity encoding in a base station including transmission antennas, comprises: a cell search unit for detecting frame timing information and scrambling codes of the base station from signals output from the base station; a descrambling unit for descrambling the signals output from the base station using the frame timing information and the scrambling codes; an accumulation processor for despreading the descrambled signals; a depatternization unit for depatternizing the despread signals using pilot symbol patterns corresponding to the two transmission antennas; and an accumulator bank unit for performing accumulation and addition processes of the depatternized signals to output signals corresponding to the transmission antennas.

Abstract: Disclosed is an apparatus and method for processing a ranging channel in an OFDMA system. The apparatus converts received ranging complex signals to polar coordinate signals having a signal magnitude and a phase, and the received converted signals are each represented by a signal magnitude component and a phase component. A predetermined phase component of a signal according to a phase rotation is used to estimate a time delay by an addition operation of the phase of the received signal and the phase according to the phase rotation. Accordingly, the time delay and the power of each reverse link user of the OFDMA mobile communication system can be calculated by arithmetic operations of addition components instead of multiplication components, resulting in the reduction of complexity.

Abstract: A system in an asynchronous mobile communications system and located in a mobile station for determining use of space-time block-coding-based transmit diversity encoding in a base station including transmission antennas, comprises: a cell search unit for detecting frame timing information and scrambling codes of the base station from signals output from the base station; a descrambling unit for descrambling the signals output from the base station using the frame timing information and the scrambling codes; an accumulation processor for despreading the descrambled signals; a depatternization unit for depatternizing the despread signals using pilot symbol patterns corresponding to the two transmission antennas; and an accumulator bank unit for performing accumulation and addition processes of the depatternized signals to output signals corresponding to the transmission antennas.